1. Field of the Invention
The invention relates to a data transmission system and method, and more particularly to a data transmission system and method for a serial transmission device.
2. Description of the Related Art
A Universal Serial Bus (USB) is widely used in various electronic devices for data transmission between a host and peripheral devices. A USB 1.0 standard provides 1.5 Mbps (low-speed) and 12 Mbps (full-speed) data rates. A USB 2.0 standard provides 480 Mbps (high-speed) data rates. A USB 3.0 standard is presently being promoted, which provides 4.8 Gbps (super speed) data rates. Please refer to the “Universal Serial Bus 3.0 Specification” for further detail.
In a USB 2.0 protocol, a USB 2.0 HUB is compatible with a USB 1.0 device. FIG. 1 shows a schematic illustrating a USB 3.0 system with a USB 2.0 HUB and a USB 3.0 HUB. However, in a USB 3.0 protocol, no stipulation is made for a USB 3.0 HUB to be compatible with a USB 2.0 device. Thus a USB 2.0 device 111 can only use a USB 2.0 protocol to perform data transmission for the host 107 via the USB 2.0 HUB 101. Thus, a USB 2.0 device can not use a higher speed to perform data transmission for a host, even though a system thereof supports the USB 3.0 protocol for data transmission. Thus, it is a hindrance for improving performance of a USB 3.0 system, that the USB 2.0 device can not use a USB 3.0 bandwidth, which is 10 times that of a USB 2.0. Therefore, a data transmission system and method thereof for translating a USB 2.0 device into a USB 3.0 device is desired, so as to increase data transmission rate of the USB 2.0 device within a USB 3.0 system and performance of the USB 3.0 system.